New and improved fastening means



Oct. 15, 1963 o. O. KYTTAY ,1

NEW AND IMPROVED FASTENING MEANS Filed Dec. 14, 1959 3125-4 1515-5 EIEIE INVENTOR.

osg Aw 0. KYTTA ATTO NEY.

United States Patent ce 3,106,759 NEW AND IMPRGVED FASTENING MEANSOswald 0. Kytta, South Bend, Ind, assignor to The Bendix Corporation, acorporation of Delaware Filed Dec. 14, 1959, Ser. No. 859,333 6 Claims.(tCl. 24--2t)5.17)

The present invention relates to new and improved fastening means; andmore particularly to new and improved means for fastening two ringshaped structures together.

In some types of power braking units that are manufactured today, apremolded rubber diaphragm is clamped between a pair of members having apair of juxtaposed abutment ring shaped surfaces.

An object of the present invention is the provision of a more simplifiedand inexpensive structure for clamping and holding the diaphragm betweenthe juxtaposed members.

The invention resides in certain constructions and combinations andarrangements of parts; and further objects and advantages of theinvention will become apparent to those skilled in the art to which itrelates from the following description of the several preferredembodiments described with reference to the accompanying drawing forminga part of this specification, and in which:

FIGURE 1 is an end view of a couple of circular plates having adiaphragm clamped therebetween by means of the new and improvedfastening structure of the present invention;

FIGURE 2 is a fragmentary cross sectional view taken approximately onthe line 2-2 of FIGURE 1 and showing one embodiment of the invention;

FIGURE 3 is a cross sectional view similar to FIGURE 2 and showinganother embodiment of the invention;

FIGURE 4 is a fragmentary cross sectional view similar to FIGURE 2 andshowing still another embodiment of the invention;

FIGURE 5 is an end view of a portion of the structure shown in FIGURE 4;and

FIGURE 6 is a cross sectional view taken approximately on the line 6-6of FIGURE 5.

In an effort to reduce the cost of power braking devices of the generaltype shown in the Earl R. Price Patent No. 2,818,710, it has been foundfeasible to make the front and rear half sections of the power piston ofplastic; and as stated above, it is an object to provide cheaper andmore simple means for fastening this type of structure together. It willbe understood that the structure shown and described will have otherapplications, particularly where a resilient memben'such as a diaphragm, is clamped between two rigid members such that a separatingforce is applied to the two rigid members at all times.

In the structure shown in the drawing, the front half section of thepower piston shown in the above referred to patent is generallyindicated at 10, and the rear piston section of the structure shown in'the above referred to patent is generally indicated at 12. The outeredge of the diaphragm I4 is sandwiched between the annular outer edge ofthe piston sections 10 and 12 and is held in sealing engagementtherewith by means of the novel structure of the present invention. a

In the structure shown in FIGURES 1 and 2 of the drawing, the rearpiston section 12 is, of course, made of plastic and is provided with aplurality of integral forwardly projecting shafts 16 (only three ofwhich are shown) and which extend through aligned openings in the frontpiston section 10. The ends of the shafts 16 which project out of thefront end of the openings in the front piston section 10 are generallyheaded as at to 3,106,759 Patented Oct. 15, 1963 provide a radiallyoutwardly extending shoulder 22 which engages the front end face of thefront piston section 10. The distance between the shoulder 22 and thefront face of the rear piston section 12 is provided with a length whichrequires that the diaphragm 14 be compressed by a predetermined amountwhen the front piston section It) and diaphragm 14 are sandwichedtherebetween. The projecting, or headed ends 20 of the shafts 18 areslotted, as for example by a saw or screw slotting machine, to a depthwhich extends inwardly of the shoulder 20 by an amount which permits theslot separated sections of the shaft 20 to be bent together. Where bothhalves of the shaft are provided with a shoulder 22, the slot 24 ispreferably of a width approximately twice that of the shoulders 22 sothat the outer edge of the heads 29 can be forced through the openings18 from the rear end face of the front section 10. To aid in thisrespect, the front end of the heads 20 are preferably tapered as at 26.

The sections 10 and 12 of the piston are subject to rapid reversal offorces, as by vibration, which in time would wear the shoulders 22 andthereby permit the heads 20 to be withdrawn out of the opening 18. Toprevent this from happening, a circular wire 28 is wedged in the ends ofthe slots 24 of each of the shafts 16 to hold their shoulders 22 intofirm engagement with the front face of the front piston section 10.Inasmuch as the shafts 16 are made of plastic which deforms slightlywith time and pressure, the sidewalls of the slots 24 will deformarcuately about the wire 28 to a slight degree to form recesses whichhelp retain the wire 28. With materials which do not deformunder timeand pressure, it may be desirable to form arcuate recesses 30 in thesidewalls of the slots 24 for this purpose. Where this is done, it willbe seen that the wire 28 being wider than the slots 24, will force theopposite halves of the heads 20 radially outwardly from their normalposition while the wire 28 is being forced into the end of'the slots;and in order to permit this to happen it may be preferable to form aslight groove 32 at the juncture of the shoulders 22 and the cylindricalsection of the shafts 16. The grooves 32 permit adjacent section of theshafts 16 to yield with respect to the opposite halves of the head 20during insertion of the 3: differs principally from that shown in FIGURE2 in that the shaft 16 is not formed integrally on the rear pistonsection 12', but is provided with a large head'portion 34 which abutsthe rear face of the rear piston section 12, and has a shaft section 16'which passes through an opening 36 in the rear piston section 12'. Inthe embodiment shown in FIGURE 3, the front and rear piston sections It)and 12 are made of pot metal and the fastener structure shown in FIGURE3 is also made of metal. The head 20 is intended to be forced throughboth of the openings 36 and 18 and the shoulders 22' snap into positionin the same manner as described for the embodiment correspond to thoseof the other views carry the same reference numeral characterizedfurther in that a double prime mark is aflixed thereto The centerportion of the strip 38 is provided with oppositely facing bend-overportions 40 and 42 to form shoulders for abutment with the rear face ofthe rear piston section 12" and the forwardly facing end portions of thestrip 38 are generally arcuately bent to provide a stem portion 16"whose outer surface is in general engagement with the sidewalls of theopening 36" and opening 18". The projecting ends of the legs 44 and 46are first rounded radially inwardly to provide the grooves 32", arethereafter deformed radially outwardly to provide the shoulders 22". Thelegs 44 and 46 are thereafter inclined inwardly to provide conicalsurfaces 26" which will spring the legs 44 and 46 together when they areinserted through the openings in the piston sections. Recesses 36" areprovided in the adjacent edges of the legs 44 and 46 just forwardly ofthe shoulders 22 to retain the wire 23" when it is pressed intoposition. The strips 38 are used in the same manner as the fastenersshown in FIGURE 3, and they function in generally the same manner toprovide generally the same results.

While the several embodiments have been described as using slottedshafts the opposite side sections of which both include a shoulder 22,it will be understood that in some instances only one shoulder need beprovided to hold the structure together. Where only one shoulder isprovided, the width of the slot 24 need only be approximately equal tothe width of the shoulder 22 in order to permit the head of the shaft tobe inserted through the opening 18.

While the several embodiments of the invention have been described inconsiderable detail, I do not wish to be limited to the particularconstructions shown and described; it is my intention to cover herebyall novel adaptations, modifications and arrangements thereof which comewithin the practice of those skilled in the art to which the inventionrelates.

I claim:

1. A fastening structure for a pair of members having ring shapedjuxtaposed abutment portions at least one of which portions has aplurality of cylindrically shaped openings therethrough and comprising:a plurality of headed shafts projecting through said openings in saidone of said members and retained by the other of said members from beingpulled through said openings, the portions of said shafts which projectout of said openings in said one of said members having radiallyoutwardly extending shoulders of predetermined width and which abut theouter face of said one of said members surrounding its openings and thesurface of each shaft between said shoulder and head being cylindricalin its normal condi tion to engage the sidewalls of said cylindricalopenings when inserted therein, each of said projecting shaft portionsalso having a longitudinally extending slot of a width approximatelytwice said predetermined shoulder width, and an arcuately bent wireextending around and wedged in the slot of each of said shafts to holdtheir shoulders in engagement with said outer face of said one of saidmembers.

2. A fastening structure for a pair of members having ring shapedjuxtaposed abutment portions having a plurality of cylindrically shapedand aligned openings therethrough and comprising: a plurality of headedshafts the shaft portions of which project through said openings withtheir heads in engagement with one of said members and their shaftsextending out of the opening in the other of said members, the portionsof said shafts which project out of said openings in said other one ofsaid members having radially outwardly extending shoulders ofpredetermined width and which abut the outer face of said other one :ofsaid members surrounding its openings and the surface of each shaftbetween said shoulder and head being cylindrical in its normal conditionto engage the sidewalls of said cylindrical openings when insertedtherein, each of said projecting shaft portions also having alongitudinally extending slot of a width approximately twice saidpredetermined shoulder width, an arcuately bent wire extending aroundand wedged in the slot of each of said shafts to hold their shoulders inengagement with said outer face of said other one of said members, andeach shaft having a recess in its cylindrical surface adjacent itsshoulder to permit fiexure of said shaft during insertion of said wire.

3. A fastening structure according to claim 1 and fur-. thercharacterized in that said shafts are integral with said portionabutting the portion having said cylindrical openings.

4. A fastening structure according to claim 1 wherein said shaftcomprises a strip of sheet metal having oppositely facing radiallyoutwardly extending folded over portions adjacent its center forming theshoulder portion of a head and which engages one of said abutmentportions, and longitudinally extending leg portion of arcuately bentcross section which extend through and engage the sidewalls of saidcylindrical openings, said leg portions extending out of the oppositeend of said opening in the other one of said abutment portions and saidprojecting end portions of said legs having laterally outwardly turnedportions providing shoulders for engaging the opposite end face of saidother one of said abutment portions.

5. A fastening structure according to claim 3 and further characterizedin that said integral shafts are recessed adjacent said shoulders topermit fiexure of said shaft during insertion of said wire.

6. A fastening structure according to claim 2 wherein said shaftscomprise:

a strip of sheet metal having oppositely facing radially outwardlyextending folded over portions adjacent its center forming the shoulderportion of a head and which engages one of said abutment portions, andlongitudinally extending leg portions of arcuately bent cross sectionwhich extend through and engage the sidewalls of said cylindricalopenings, said leg portions extending out of the opposite end of saidopening in the other one of said abutment portions and said projectingend portions of said legs having laterally outwardly turned portionsproviding shoulders for engaging the opposite end face of said other oneof said abutment portions.

References Cited in the file of this patent UNITED STATES PATENTS531,363 Dinlzelacker Dec. 25, 1894 1,754,209 Carr Apr. 8, 1930 2,440,341Lehman et al Apr. 27, 1948 2,564,101 Dzus Aug. 14, 1951 FOREIGN PATENTS1,111,742 France Nov. 2, 1955 569,618 Germany Feb. 6, 1933

1. A FASTENING STRUCTURE FOR A PAIR OF MEMBERS HAVING RING SHAPEDJUXTAPOSED ABUTMENT PORTIONS AT LEAST ONE OF WHICH PORTIONS HAS APLURALITY OF CYLINDRICALLY SHAPED OPENINGS THERETHROUGH AND COMPRISING:A PLURALITY OF HEADED SHAFTS PROJECTING THROUGH SAID OPENINGS IN SAID OFSAID MEMBERS AND RETAINED BY THE OTHER OF SAID MEMBERS FROM BEING PULLEDTHROUGH SAID OPENINGS, THE PORTIONS OF SAID SHAFTS WHICH PROJECT OUT OFSAID OPENINGS IN SAID ONE OF SAID MEMBERS HAVING RADIALLY OUTWARDLYEXTENDING SHOULDERS OF PREDETERMINED WIDTH AND WHICH ABUT THE OUTER FACEOF SAID ONE OF SAID MEMBERS SURROUNDING ITS OPENINGS AND THE SURFACE OFEACH SHAFT BETWEEN SAID SHOULDER AND HEAD BEING CYLINDRICAL IN ITSNORMAL CONDITION TO ENGAGE THE SIDEWALLS OF SAID CYLINDRICAL OPENINGSWHEN INSERTED THEREIN, EACH OF SAID PROJECTING SHAFT PORTIONS ALSOHAVING A LONGITUDINALLY EXTENDING SLOT OF A WIDTH APPROXIMATELY TWICESAID PREDETERMINED SHOULDER WIDTH, AND AN ARCUATELY BENT WIRE EXTENDINGAROUND AND WEDGED IN THE SLOT OF EACH OF SAID SHAFTS TO HOLD THEIRSHOULDERS IN ENGAGEMENT WITH SAID OUTER FACE OF SAID ONE OF SAIDMEMBERS.